Anti-inflammatory bioactive glass particulates

ABSTRACT

Compositions and methods for systemically minimizing the inflammatory effects of TNF-α are disclosed. The compositions include particles of bioactive glass with a particle size less than about 20 μm, alone or in combination with anti-inflammatory agents and other therapeutic agents. The compositions can include an appropriate carrier for oral, intramuscular, intraperitoneal or intravenous administration. When administered to a patient, the particles bring about elevated levels of IL-6 and do not cause elevated levels of TNF-α.

[0001] This application is a divisional application of U.S. applicationSer. No. 09/560,475, filed Apr. 28, 2000, which claims the prioritybenefit of U.S. Provisional Application No. 60/131,529, filed Apr. 29,1999. The entire content of U.S. application Ser. No. 09/560,475 andU.S. Provisional Application No. 60/131,529 are hereby incorporatedherein by reference.

FIELD OF THE INVENTION

[0002] The present invention relates to compositions and methods for usein the transient suppression of the inflammatory response by suppressingplasma levels of tissue necrosis factor-alpha and increasing plasmalevels of interleukin-6.

BACKGROUND OF THE INVENTION

[0003] When an injury occurs, cell damage initially comes from theprecipitating event, such as a cut, resulting in ruptured cells andsevered or crushed capillaries and other blood vessels. The interruptionof blood flow results in anoxia, causing the death of additional cells.The wound site quickly fills with dead and dying cells, extracellularsubstances (collagen, elastic fibers, fat and ground substances),extravasated blood, and possibly bacteria and viruses introduced duringthe injury.

[0004] Tissue damage is not restricted to the initial area of injury,and may increase over the next several hours or days as a result of therelease of lysomal enzymes from the injured cells or as a consequence ofinflammation (swelling) and/or infection. (See Reese et al., Role ofFibronectin in Wound Healing, the subject matter of which is herebyincorporated by reference.) The inflammatory response is one of thenormal stages of wound healing, and is necessary for subsequent phasesof healing.

[0005] Inflammation is a vital process necessary for an organism tosurvive an external insult, such as a wound or burn. However, ifunchecked, inflammation can have harmful consequences. For example, manychronic and even life-threatening disorders, such as asthma, rheumatoidarthritis, lung fibrosis, peritoneal adhesions, hypersensitivity andautoimmune diseases are a result of an uncontrolled inflammatoryresponse. An unresolved inflammation in the lung resulting frombacterial infection (i.e., pneumonia) may eventually lead to extensivetissue damage and a chronic lung abscess. Inflammation of the peritonealcavity, for example, and the resulting adhesions following abdominalsurgery is a major cause of infertility in women. Asthma is an oftenlife-threatening disorder which results from an inadvertently stimulatedinflammatory response in the lungs. An excessive inflammatory responsecan cause extensive swelling, which can lead to additional injury as aresult of anoxia. Pain results from a combination of kinins and theeffect of lysozymes and pressure from the swelling on nerve endings.Unchecked, the inflammatory response can set off a neural feedback loopand cause hyperalgesia, a phenomenon in which the surrounding area ofinjury remains painful. Accordingly, there is a great interest in themedical community to develop anti-inflammatory agents.

[0006] Many known anti-inflammatory compositions reduce the inflammatoryresponse, but are also immunosuppressive. For example, corticosteroidsare potent anti-inflammatory agents, but are associated with T-cellsuppression and increased infections. Interleukin-10 (as well as IL-4and IL-3 to lesser extents) are broadly acting anti-inflammatory agents,but are associated with decreased cell mediated immune functions.

[0007] It would be advantageous to provide compositions and methodswhich provide protection from adverse effects associated withinflammation, preferably without unnecessary immunosuppression. Thepresent invention provides such compositions and methods.

SUMMARY OF THE INVENTION

[0008] Compositions and methods for providing protection from adverseeffects associated with inflammation are disclosed. The compositions andmethods can suppress plasma concentrations of tissue necrosisfactor-alpha (TNF-α) while increasing plasma concentrations ofinterleukin-6 (IL-6).

[0009] The compositions include non-interlinked particles of bioactiveglass with a size less than about 20 μm, alone or in combination with anadditional anti-inflammatory agent, and optionally include othertherapeutic agents. Formulations including the composition and asuitable carrier, preferably for oral, intramuscular, intraperitoneal orintravenous administration, are also disclosed.

[0010] The composition can be administered orally, intramuscularly,intraperitoneally or intraveneously to provide systemic relief from theadverse effects associated with inflammation, for example, the effectsof excess TNF-α.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011]FIG. 1 is a graph showing the number of cells (cells/ml×10⁴) formice injected intraperitoneally with control and with bioactive glass,as described in Example 1.

[0012]FIG. 2 is a graph showing the concentration of TNF-α (pg/ml) formice injected intraperitoneally with control and with bioactive glass,as described in Example 1.

[0013]FIG. 3 is a graph showing the concentration of IL-6 (pg/ml) formice injected intraperitoneally with control and with bioactive glass,as described in Example 1.

[0014]FIG. 4 is a graph showing the concentration of IL-6 (pg/ml) formice injected intraperitoneally with varying doses of bioactive glass,as described in Example 2.

[0015]FIG. 5 is a graph showing the concentration of TNF-α (pg/ml) formice injected intraperitoneally with bioactive glass andLPS/D-galactosamine, as described in Example 2.

[0016]FIG. 6 is a graph showing the concentration of TNF-α (pg/ml) formice injected intraperitoneally with bioactive glass and LPS, asdescribed in Example 2.

[0017]FIG. 7 is a graph showing the concentration of IL-1α (pg/ml) formice injected intraperitoneally with bioactive glass and LPS, asdescribed in Example 2.

[0018]FIG. 8 is a graph showing the concentration of IL-6 (pg/ml) formice injected intraperitoneally with bioactive glass and LPS, asdescribed in Example 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Compositions and methods for providing protection from adverseeffects associated with inflammation are disclosed. The compositions andmethods can suppress plasma concentrations of tissue necrosisfactor-alpha (TNF-α) while increasing plasma concentrations ofinterleukin-6 (IL-6).

[0020] The compositions can be administered orally, intramuscularly,intraperitoneally or intraveneously to provide systemic relief from theadverse effects associated with inflammation, for example, the effectsof excess TNF-α. The bioactive glass is bioactive in vivo, and is notpro-inflammatory. It does not cause the recruitment of PMNs and does notstimulate TNF-αsecretion. It stimulates IL-1, release very modestly, andinduces an IL-6 response.

[0021] IL-6 is a unique cytokine with pro- and anti-inflammatoryproperties. It is the primary hepatic acute phase response inducer (apro-inflammatory effect). It suppresses TNF-α production by macrophages(an anti-inflammatory effect), promotes B-cell proliferation andpromotes a Th₂ response, and is mitogenic for some cell types. It hasbeen shown to reduce collagen induced arthritis (Immunology, 95(1):31(1998)) and to reduce monocyte-mediated TNF production in response toLPS (Exp. Cell Res., 215(1):51-56 (1994) and Am. J. Physiol. 267(4pt.1):L442-446 (1994)).

[0022] The compositions include non-interlinked particles of bioactiveglass with a size less than about 20 μm, alone or in combination with anadditional anti-inflammatory agents, and optionally include othertherapeutic agents. Formulations including the composition and asuitable carrier, preferably for oral or intravenous administration, arealso disclosed.

[0023] The normal inflammatory effect is generally regarded as beingligand/receptor controlled. Not being bound to any particular theory ormechanism, it is believed that the rate and amount of ions generated bythe absorption of the small particles of bioactive glass has an effecton the pro-inflammatory receptors, which is responsible for thesuppression of the cytokines involved in the inflammatory process.Further, the surface of the small particles is micro-porous, and mayadsorb the cytokines, rendering them inactive in the inflammatoryprocess.

[0024] The compositions and methods described herein are advantageousbecause they reduce the inflammatory response, but are not broadlyimmunosuppressive. There does not appear to be a typical dose dependencyin terms of particles of bioactive glass and IL-6 response. The responseis independent of dose up to extremely high levels of particulate, forexample, over XXX mg injection. Further, the bioactive glass particlesappear to elicit a specific IL-6 response, transient in nature, lastingon the order of several hours. Pre-exposure to bioactive glass particlesresults in a significantly attenuated pro-inflammatory IL-6 cytokineresponse that results in the suppression of a typical inflammatoryresponse caused by injection of an endotoxin after the injection of thebioactive glass particles.

[0025] The terms “wound” and “burn,” collectively referred to herein as“injury” have their usual meanings. “Wound” is intended to includewounds caused by surgical procedures. “Normal” is used in the sense itis usually used in the medical arts. “Medical practitioner” means one ofordinary skill in the art wound and burn treatment. Typically, thisperson is a physician, nurse, dentist, or paramedic.

[0026] I. Bioactive Glass

[0027] Compositions including non-interlinked particles of bioactiveglass with an average diameter of less than about 20 μm, alone or incombination with anti-inflammatory agents, can be used for the methodsdescribed herein.

[0028] Very small particulate bioactive glass has the property ofexerting an anti-inflammatory effect when administered systemically. Itappears that the bioactive glass suppresses the production of tissuenecrosis factor alpha (TNF-α). TNF-α is a powerful pro-inflammatorycytokine that not only participates in the normal inflammatory response,but is also implicated in myocardial dysfunction and cardiomyocyte deathin ischemia-reperfusion injury, sepsis, chronic heart failure, viralmyocarditis and cardiac allograft rejection, as well as a host of otherinflammatory disorders. Accordingly, by suppressing the production ofTNF-α, the compositions reduce the likelihood of these disordersoccurring.

[0029] The preferred size range for the bioactive glass, for thisembodiment, is such that the particles do not physically obstructvascular, lymph or pulmonary pathways as the particles pass through thebody. As the particles are less than about 20 microns in size, theyavoid phagocytosis and uptake by the reticuloendothelial system. This isin stark contrast to small particles of other materials, such as talcum,asbestos, silicone and metal debris, which are known to be stronglypro-inflammatory. The particles are of a suitable size for intravenousadministration.

[0030] As used herein the terms “bioactive glass” or “biologicallyactive glass” mean an inorganic glass material having an oxide ofsilicon as its major component and which is capable of bonding withgrowing tissue when reacted with physiological fluids.

[0031] Bioactive glasses are well known to those skilled in the art, andare disclosed, for example, in An Introduction to Bioceramics, L. Henchand J. Wilson, eds. World Scientific, New Jersey (1993), the contents ofwhich are hereby incorporated by reference.

[0032] The glass preferably includes between 40 and 86% by weight ofsilicon dioxide oxide (SiO₂), between about 0 and 35% by weight ofsodium oxide (Na₂O), between about 4 and 46% by weight calcium oxide(CaO), and between about 1 and 15% by weight phosphorus oxide (P₂05).More preferably, the glass includes between 40 and 60% by weight ofsilicon dioxide oxide (SiO₂), between about 5-30% by weight of sodiumoxide (Na₂O), between about 10 and 35% by weight calcium oxide (CaO),and between about 1 and 12% by weight phosphorus oxide (P₂O5). Theoxides can be present as solid solutions or mixed oxides, or as mixturesof oxides.

[0033] CaF₂, B₂O₃, Al₂O₃, MgO and K₂O may be included in the compositionin addition to silicon, sodium, phosphorus and calcium oxides. Thepreferred range for B₂O₃ is between 0 and 10% by weight. The preferredrange for K₂O is between 0 and 8% by weight. The preferred range for MgOis between 0 and 5% by weight.

[0034] The most preferred glass is Bioglass®™ (a trademark of Universityof Florida), which has a composition including about 45% by weightsilicon dioxide, about 24.5% by weight sodium oxide, about 6% by weightphosphorus oxide, and about 24.5% by weight calcium oxide. Anotherpreferred material is hydroxyapatite.

[0035] Particulate, non-interlinked bioactive glass is preferred in thepresent invention. That is, the glass is in the form of small, discreteparticles, rather than a fused matrix of particles or a mesh or fabric(woven or non-woven) of glass fibers. Note that under some conditionsthe discrete particles of the present invention may tend to clingtogether because of electrostatic or other forces but are stillconsidered to be non-interlinked. The particle size is less than about20 microns, preferably 10 microns or less, more preferably less thanabout 5 microns, and ideally, less than about 2 microns.

[0036] The glass composition can be prepared in several ways, to providemelt-derived glass, spun fibers of sol-gel derived glass, and sinteredglass particles. The sintered particles may be in sol-gel derived, orpre-reacted melt derived form. Sol-gel derived glass is generallyprepared by synthesizing an inorganic network by mixing metal alkoxidesin solution, followed by hydrolysis, gelation, and low temperature(600-900° C.) firing to produce a glass. Melt derived glass is generallyprepared by mixing grains of oxides or carbonates, melting andhomogenizing the mixtures at high temperatures, typically between about1250 and 1400° C. The molten glass can be fritted and milled to producea powder or casted into steel or graphite molds to make bulk implants.

[0037] The glass composition is preferably melt-derived. In eachpreparation, it is preferred to use reagent grade glass, especiallysince the glass is used to prepare materials which ultimately may beimplanted in a human. Other compositions which biodegrade and releasethe same ions as the bioactive glasses described above can also be used,provided they do not elicit an inflammatory response and that they alsoelicit enhanced IL-6 production.

[0038] A. Melt Derived Glass

[0039] A melt-derived glass composition can be prepared, for example, bypreparing an admixture of the individual metal oxides and othercomponents used to prepare the glass composition, blending theadmixture, melting the admixture, and cooling the mixture. The meltingtemperature is determined in large part by the glass composition, andranges, for example, from about 900-1500° C., preferably between about1250 and 1450° C. The melt is preferably mixed, for example, by oxygenbubbling, to ensure a thorough homogenation of the individualcomponents.

[0040] The mixture can be cooled, for example, by adding the moltenadmixture to a suitable liquid, such as deionized water, to produce aglass frit. Porosity can be introduced by grinding the glass into apowder, admixing the powder with a foaming agent, and hot pressing themixture under vacuum and elevated temperature. The particle size of theglass powder is between about 40 and 70 μm, the vacuum is preferablyless than 50 MPa, and the hot pressing is preferably performed at atemperature above 400° C., preferably between about 400 and 500° C.Suitable foaming agents include compounds which evolve carbon dioxideand/or water at elevated temperatures, for example, metal hydroxides,metal carbonates, and peroxides, such as hydrogen peroxide. Preferredmetal carbonates are sodium bicarbonate, sodium carbonate and calciumcarbonate. The foaming agents are preferably added in a range of betweenabout 1-5, more preferably 2-3 percent by weight of the glass powder.The preparation of melt-derived porous glass is described, for example,in U.S. Pat. No. 5,648,301 to Ducheyne and El Ghannam, the contents ofwhich are hereby incorporated by reference.

[0041] B. Sintered Glass Particles

[0042] Glass can be sintered using known methodology. In one embodiment,an aqueous slurry of the glass powder and a foaming agent with asuitable binder, such as polyvinyl alcohol, is formed. The slurry isthen poured into a mold, allowed to dry, and sintered at hightemperatures. These temperatures may range, depending on the glasscomposition and foaming agent used, between about 500 and 1000° C., morepreferably between about 600 and 800° C.

[0043] C. Spun Fibers of Sol-gel Derived Glass

[0044] It is known in the art to control the heat treatment cycle ofglass gels to control the pores and interpores of the material to createa porous glass material. Suitable pore diameters are between 20 and 180Å, suitable pore volumes are between 40 and 52 cc/g, and suitablesurface areas are between 75 and 350 m²/g. Since a pore diameter largerthan 0.1 microns is difficult to achieve using this method, thesintering and foaming processes described herein are generally morepreferred.

[0045] D. Leaching of the Porous Material

[0046] To aid in preparing glass compositions with high porosity, theglass composition can include a material which can be preferably leachedout of the glass composition, and, in doing so, provide the compositionwith high porosity. For example, minute particles of a material capableof being dissolved in a suitable solvent, acid, or base can be mixedwith or melted into the glass, and subsequently leached out. Theresulting voids have roughly the same size as the particle that wasleached out. In the case of a material which is part of a melt-derivedglass composition, the size of the pores and degree of porosity dependson the amount of added material relative to the amount of glass. Forexample, if the leached material constituted about 80% of the glass,then the glass would be approximately 80% porous when the material wasleached out. When leaching the glass composition, care should be takennot to leach out those components which add to the bioactivity of theglass, i.e., the calcium and phosphorus oxides.

[0047] II. Formulations Including Bioactive Glass

[0048] The bioactive glass particulates are preferably administered in aformulation that includes an acceptable carrier for the mode ofadministration. Suitable pharmaceutically acceptable carriers are knownto those of skill in the art. The formulations can optionally includeother therapeutically active ingredients, such as antibiotics,antivirals, healing promotion agents, anti-inflammatory agents,immunosuppressants, growth factors, anti-metabolites, cell adhesionmolecules (CAMs), antibodies, vascularizing agents, anti-coagulants, andanesthetics/analgesics.

[0049] The carrier must be pharmaceutically acceptable in the sense ofbeing compatible with the other ingredients of the formulation and notdeleterious to the recipient thereof. The formulations can includecarriers suitable for oral, rectal, topical or parenteral (includingsubcutaneous, intramuscular and intravenous) administration. Preferredcarriers are those suitable for oral or parenteral administration.

[0050] Formulations suitable for parenteral administration convenientlyinclude a sterile aqueous preparation of the bioactive glass. Suchformulations may conveniently contain distilled water, 5% dextrose indistilled water or saline. The formulations may be in the form of apowdered formulation including the bioactive glass particulates andsalt, dextrose, buffers and the like, which can be dissolved in waterimmediately prior to administration.

[0051] For enteral administration, the bioactive glass particulates canbe incorporated into an inert carrier in discrete units such ascapsules, cachets, tablets or lozenges, each containing a predeterminedamount of the particles; as a powder or granules; or a suspension orsolution in an aqueous liquid or non-aqueous liquid, e.g., a syrup, anelixir, an emulsion or a draught. Suitable carriers may be starches orsugars and include lubricants, flavorings, binders, and other materialsof the same nature.

[0052] A tablet may be made by compression or molding, optionally withone or more accessory ingredients. Compressed tablets may be prepared bycompressing in a suitable machine the active compound in a free-flowingform, e.g., a powder or granules, optionally mixed with accessoryingredients, e.g., binders, lubricants, inert diluents, surface activeor dispersing agents. Molded tablets may be made by molding in asuitable machine, a mixture of the powdered active compound with anysuitable carrier.

[0053] A syrup or suspension may be made by adding the active compoundto a concentrated, aqueous solution of a sugar, e.g., sucrose, to whichmay also be added any accessory ingredients. Such accessory ingredientsmay include flavoring, an agent to retard crystallization of the sugaror an agent to increase the solubility of any other ingredient, e.g., asa polyhydric alcohol, for example, glycerol or sorbitol.

[0054] In addition to the aforementioned ingredients, the formulationsmay further include one or more optional accessory ingredient(s)utilized in the art of pharmaceutical formulations, e.g., diluents,buffers, flavoring agents, binders, surface active agents, thickeners,lubricants, suspending agents, preservatives (including antioxidants)and the like.

[0055] Other Therapeutic Agents

[0056] In addition to bioactive glass particles, the formulations caninclude other therapeutic agents such as antibiotics, antivirals,healing promotion agents, anti-inflammatory agents, immunosuppressants,growth factors, anti-metabolites, cell adhesion molecules (CAMs), bonemorphogenic proteins (BMPs), vascularizing agents, anti-coagulants, andtopical anesthetics/analgesics.

[0057] The antibiotics can be topical antibiotics suitable for skintreatment. Examples of such antibiotics include but are not limited to:chloramphenicol, chlortetracycline, clyndamycin, clioquinol,erythromycin, framycetin, gramicidin, fusidic acid, gentamicin,mafenide, mupiroicin, neomycin, polymyxin B, bacitracin, silversulfadiazine, tetracycline and chlortetracycline.

[0058] Suitable antivirals include topical antivirals, such as acyclovirand gancyclovir. Suitable anti-inflammatory agents includecorticosteroids, hydrocortisone and nonsteroidal antinflammatory drugs.Suitable growth factors include basic fibroblast growth factor (bFGF),epithelial growth factor (EGF), transforming growth factors α and β (TGFα and β), platelet-derived growth factor (PDGF), and vascularendothelial growth factor/vascular permability factor (VEGF/VPF)).Suitable topical anesthetics include benzocaine and lidocaine.

[0059] An additional anti-inflammatory agent which can be used incombination with the bioactive glass particles is β-glucan. β-glucan isa polysaccharide with anti-inflammatory properties, and, like thebioactive glass particles described herein, increases IL-6 release anddecreases TNF-αand IFN_(Y) release.

[0060] III. Methods of Reducing Inflammation

[0061] The compositions can be used to prophylactically ortherapeutically to reduce inflammation in a patient. Overly acute orchronic inflammation can result in various disease states in a patient,for example, arthritis and tendonitis, pulmonary disorders such asasthma and emphysema, and post-surgical (peritoneal) adhesions.

[0062] The particles of bioactive glass are believed to modify theinflammatory response in the local microenvironment by altering thesynthetic properties of resident macrophages and other recruitedinflammatory cells. The particles induce macrophage tolerance byeliciting a cytokine response (IL-6 based) that acts in an autocrine andparacrine fashion.

[0063] Particles of bioactive glass can be delivered by intravenous,intramuscular, or intraperitoneal injection to provide systemic (andpossibly local when administered intramuscularly or intraperitoneally)anti-inflammatory effects. These effects can be therapeutic and/orprophylactic. For example, systemic delivery of bioactive glass can beeffective in reducing the onset of inflammation brought on by externalchallenge. Particles of bioactive glass can also be administered orally.

[0064] Systemic administration of the bioactive glass particles canlower production of TNF-αand also increase production of IL-6. Theeffect of this is to modify the pro-inflammatory response, and will beuseful in treating or preventing sepsis, systemic inflammatory responsesyndromes, adult respiratory distress syndrome, ocular injury, surgicalwound healing and adhesion formation, and delayed cutaneous woundhealing. Other disorders which are, at least in part, attributable to anexaggerated inflammatory response, such as ARDS, pancreatitis, viralhepatitis, hemorrhagic shock, ischemia/reperfusion injury, peritonealadhesions, and chronic inflammation, such as delayed wound healing andrheumatoid arthritis, can be treated with systemic administration ofbioactive glass particles.

[0065] In one embodiment, the particles are administered locally, forexample, by inhalation, by spraying (in the form of an aerosol) or bymixing the particles with a gel (for example, a biocompatible hydrogel),creme or other aqueous or non-aqueous carrier, and applying or injectingthe composition subcutaneously at a site at which surgery is to beperformed at a later time. The compositions can advantageously includean anesthetic. The presence of the particles at the proposed surgicalsite can lead to decreased inflammation resulting from the surgery.

[0066] The present invention will be more clearly understood withreference to the following non-limiting examples.

EXAMPLES Example 1 Intraperitoneal Administration of Bioactive Glass toMice

[0067] Ten mice were injected intraperitoneally with 25 mgs of bioactiveglass (45S5) with a particle size less than about 20 μm in a totalvolume of 1 ml (0.5 ml fetal calf serum and 0.5 ml phosphate-bufferedsaline) with a result pH of 9.6. An additional ten mice received thecarrier (0.5 ml fetal calf serum and 0.5 ml phosphate-buffered saline)with the pH unadjusted. Two hours later, the mice were euthanized andthe peritoneal contents were washed with 3 ml of physiologic saline.Peritoneal white cell count was performed with a hemocytometer, andperitoneal TNF-αand IL-6 determined by ELISA.

[0068] The procedures were performed without incident. The animalsappeared grossly normal for the two hour post-injection period. Atsacrifice, peritoneal white cell count in mice receiving the bioactiveglass particles was not different from peritoneal wash fluid from icereceiving only the carrier. The proinflammatory cytokine TNF-αwas notdetected in any of the samples. Peritoneal IL-6 concentrations, however,were increased 25 fold from approximately 80 pgs/ml in thecarrier-treated mice to over 2,000 pgs/ml in the bioactive glass-treatedmice. The cell count, TNF-αconcentration and IL-6 concentration from theperitoneal washings for the bioactive glass-treated mice and the controlmice are shown in FIGS. 1-3.

[0069] In conclusion, the bioactive glass is bioactive when administeredintraperitoneally. The bioactive glass is not acting as a classicalirritant. A chemical irritation or a direct inflammatory agent likeendotoxin or TNF-αwould have resulted in a significant and rapidneutrophil influx, which was not observed. The bioactive glass was notdirectly pro-inflammatory, since no TNF-αresponse was elicited. Asignificant IL-6 response was observed, but IL-6 has bothpro-inflammatory (hepatic acute phase induction) and anti-inflammatoryproperties (delays apoptosis, suppresses macrophase TNF and IL-1production). Since no inflammatory cell influx was observed, theenhanced IL-6 production must have been secondary to residentmacrophages and fibroblasts. The results are consistent with bioactiveglass-mediated stimulation of resident cell IL-6 synthesis, whichrepresents a new anti-inflammatory property.

Example 2 Anti-Inflammatory Effect of Bioactive Glass in a MouseEndotoxicosis Model

[0070] Bioactive glass particles with a particle size of 5 μm wereinjected to C57B1/6 mice. The mice were injected ip with 3, 6, 12, 25and 50 mg of bioactive glass particles or buffer. The animals weresacrificed and TNF-α, IL-1α and IL-6 levels were determined in theperitoneal lavage fluid at 2 hours (FIG. 4). In a second study, micewere injected with 12 mg of bioactive glass particles or buffer ip andthen challenged ip with 1 μg of LPS and 8 mg of D-galactosamine (Dgal) 6hours after the bioactive glass particles were administered. Bloodsamples were taken 90 minutes after Dgal/LPS injection for determinationof TNF-α. Lastly, a sublethal dose of LPS (100 ng) was given ip 2 hoursafter an ip injection of 3 mg of 5 μm particles of bioactive glass. Themice were bled, sacrificed and ravaged 2 hours after the LPSadministration.

[0071] Results: In the first study, all doses of bioactive glass werefound to induce a significant IL-6 response (range 4,584-23,112 pg/mlbioactive glass, 1,017±445 pg/ml SEM buffer); however, the bioactiveglass did not induce TNF-αor IL-1α production in the peritoneal lavagefluid. In the second study, mice that received bioactive glass particlesprior to Dgal/LPS had significantly lower plasma TNF-αthan did controls(bioactive glass: 13,047±4,126 pg/ml, control: 34,813±4,902 pg/ml,p<0.0038) (FIG. 5). Finally, peritoneal IL-6 and TNF-αwere reduced inresponse to LPS by pretreatment with bioactive glass (IL-6 24,452±6,673pg/ml and control: 53,330±2,586 pg/ml, bioactive glass: TNF-α-26±5 pg/mland control: 91±49 pg/ml) (FIGS. 6-8).

[0072] Conclusion: Bioactive glass particles are a bioactive substancethat when administered alone appear to elicit a significant initial IL-6response without concurrent expression of TNF-αor IL-1α.

We claim:
 1. A composition comprising particles of bioactive glass witha particle size less than about 20 μm in diameter and a suitable carrierfor oral, intramuscular, intraperitoneal or intravenous administration.2. The composition of claim 1, wherein the carrier is suitable forintravenous administration.
 3. The composition of claim 1, wherein thecarrier is suitable for intramuscular or intraperitoneal administration.4. The composition of claim 1, additionally comprising one or moretherapeutic agents.
 5. The composition of claim 4, wherein one or moretherapeutic agents are selected from the group consisting of healingpromotion agents, growth factors, anti-inflammatory agents, andanesthetics.
 6. The composition of claim 1 wherein the glass includesbetween about 40 and 86 percent by weight of SiO₂, between about 0 and30 percent by weight of Na₂O, between about 4 and 46 percent by weightof CaO and between about 1 and 15 percent by weight of P₂O₅.
 7. Thecomposition of claim 1, wherein the bioactive glass has a particle sizerange less than about 2 microns.
 8. A method for systemically increasingIL-6 levels in a patient, comprising administering to the patient aneffective, IL-6 increasing amount of bioactive glass particles with asize less than about 20 μm.
 9. A composition comprising particles of amaterial with a particle size less than about 20 μm which biodegrades,produces elevated serum concentrations of calcium and phosphorous ions,does not cause elevated plasma TNF-αconcentrations, and does causeelevated plasma IL-6 concentrations, in combination with a suitablecarrier for oral, intramuscular, intraperitoneal or intravenousadministration.
 10. A method for increasing IL-6 levels in a patient,comprising administering to the patient an effective, IL-6 increasingamount of bioactive glass particles with a size less than about 20 μm.11. The method of claim 10 wherein the bioactive glass particles areadministered locally.
 12. A method for increasing IL-6 levels in apatient comprising administering locally a locally effective IL-6increasing amount of bioactive glass particles with a size less thanabout 20 μm to the patient.
 13. The method of claim 12 wherein thelocally effective IL-6 increasing amount of bioactive glass particles isadministered by intraperitoneal injection.
 14. The method of claim 13wherein the locally effective IL-6 increasing amount of bioactive glassparticles is administered prophylactically or therapeutically to preventor treat peritoneal adhesions.
 15. The method of claim 13 wherein thelocally effective IL-6 increasing amount of bioactive glass particles isadministered by peritoneal injection of a composition comprising thebioactive glass particles, a suitable carrier for intraperitonealinjection, and one or more therapeutic agents.
 16. The method of claim15 wherein the one or more therapeutic agents are selected from thegroup consisting of healing promotion agents, growth factors,anti-inflammatory agents, and anesthetics.
 17. The method of claim 13wherein the bioactive glass particles have a size less than about 2microns.
 18. The method of claim 12 wherein the locally effective IL-6increasing amount of bioactive glass particles is administered byinhalation.
 19. The method of claim 12 wherein the locally effectiveIL-6 increasing amount of bioactive glass particles is administered bysubcutaneous injection.
 20. The method of claim 19 wherein the locallyeffective IL-6 increasing amount of bioactive glass particles is mixedwith a biocompatible hydrogel.
 21. The method of claim 19 wherein thelocally effective IL-6 increasing amount of bioactive glass particles isadministered at a site at which surgery is to be performed.
 22. Themethod of claim 21 wherein the locally effective IL-6 increasing amountof bioactive glass particles is mixed with an anesthetic.